add Windows taskbar control buttons (TODO: icons)

backend/windows/taskbar_buttons.c

@@ -0,0 +1,69 @@
+//go:build windows
+
+#include <windows.h>
+#include <shobjidl.h>
+#include <initguid.h>
+#include <stdio.h>
+#include "taskbar_buttons.h"
+
+DEFINE_GUID(IID_ITaskbarList3,
+    0xEA1AFB91, 0x9E28, 0x4B86, 0x90, 0xE9, 0x9E, 0x9F, 0x8A, 0x5E, 0xEF, 0xAF);
+
+static ITaskbarList3 *g_taskbar = NULL;
+static ThumbnailCallback g_callback = NULL;
+static HWND g_mainHWnd = NULL;
+static WNDPROC g_originalProc = NULL;
+
+THUMBBUTTON g_thumbButtons[3];
+
+LRESULT CALLBACK OverrideWndProc(HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam) {
+    if (msg == WM_COMMAND) {
+        int buttonId = LOWORD(wParam);
+        if (g_callback) {
+            g_callback(buttonId);
+            return 0;
+        }
+    }
+
+    return CallWindowProc(g_originalProc, hwnd, msg, wParam, lParam);
+}
+
+void hook_window_proc(HWND hwnd) {
+    g_originalProc = (WNDPROC)SetWindowLongPtr(hwnd, GWLP_WNDPROC, (LONG_PTR)OverrideWndProc);
+}
+
+int initialize_taskbar_buttons(void *hwndPtr, ThumbnailCallback cb) {
+    g_callback = cb;
+    g_mainHWnd = (HWND)hwndPtr;
+    hook_window_proc(g_mainHWnd);
+
+    CoInitialize(NULL);
+    CoCreateInstance(&CLSID_TaskbarList, NULL, CLSCTX_INPROC_SERVER, &IID_ITaskbarList3, (void**)&g_taskbar);
+
+    if (g_taskbar) {
+        g_taskbar->lpVtbl->HrInit(g_taskbar);
+    }
+
+    if (!g_taskbar || !g_mainHWnd) return -1;
+
+    ZeroMemory(g_thumbButtons, sizeof(g_thumbButtons));
+
+    g_thumbButtons[0].dwMask = THB_FLAGS | THB_TOOLTIP;
+    g_thumbButtons[0].iId = 1;
+    g_thumbButtons[0].dwFlags = THBF_ENABLED;
+    wcscpy_s(g_thumbButtons[0].szTip, ARRAYSIZE(g_thumbButtons[0].szTip), L"Previous");
+
+    g_thumbButtons[1].dwMask = THB_FLAGS | THB_TOOLTIP;
+    g_thumbButtons[1].iId = 2;
+    g_thumbButtons[1].dwFlags = THBF_ENABLED;
+    wcscpy_s(g_thumbButtons[1].szTip, ARRAYSIZE(g_thumbButtons[1].szTip), L"Play");
+
+    g_thumbButtons[2].dwMask = THB_FLAGS | THB_TOOLTIP;
+    g_thumbButtons[2].iId = 3;
+    g_thumbButtons[2].dwFlags = THBF_ENABLED;
+    wcscpy_s(g_thumbButtons[2].szTip, ARRAYSIZE(g_thumbButtons[2].szTip), L"Next");
+
+    g_taskbar->lpVtbl->ThumbBarAddButtons(g_taskbar, g_mainHWnd, ARRAYSIZE(g_thumbButtons), g_thumbButtons);
+
+    return 0;
+}